1. Field of the Invention
The present invention relates to a vehicle air conditioning system that achieves control of the blowing air temperature using a non-contact temperature sensor.
2. Description of the Related Art
A known vehicle air conditioning system includes an air conditioning (A/C) unit for supplying conditioned air, a duct system for guiding the air from the A/C unit to a blowing opening, and a contact temperature sensor for detecting the temperature of the conditioned air inside the duct. The contact temperature sensor detects the temperature of an object (blown air) with which it has physical contact. The sensor is typically a thermistor.
The air conditioner also includes an A/C computer for feedback control of the A/C unit based on the temperature detected by the sensor to cause the temperature of air blown from a blowing opening to approach its target value (see, for example, Japanese Patent Laid-Open Publication No. Hei. 6-262933).
In order to precisely achieve the target temperature, the contact temperature sensor needs to be located in the duct system as near as possible to the blowing opening, allowing for the heat loss of the air inside the duct system. Thus, for a long duct system, long electric cables are required for the connection of the contact temperature sensor near the blowing opening with the A/C computer. This leads to a high cost because of the material cost of the electric cables, and lowers assembling operation efficiency.